A promising new vaccine candidate could protect us from multiple coronaviruses - including some that haven't jumped to humans yet

• Researchers are working on a coronavirus vaccine that could protect against multiple coronaviruses.
• A new study found the shot to be highly protective against current coronavirus variants in monkeys.
• The technology could help avoid a future of seasonal booster shots.

Our current coronavirus vaccines were designed to protect us from one particular coronavirus: SARS-CoV-2, the virus responsible for this pandemic.

But the coronavirus family is large, and many researchers think a future vaccine could offer us far broader protection.

A team at the Duke Human Vaccine Institute has developed a pan-coronavirus vaccine that might be able to protect against multiple coronaviruses in the SARS family. That includes SARS-CoV-2, as well as the virus most people know as SARS - SARS-CoV-1 - which was responsible for the outbreak in 2003.

In a new study, the Duke team's vaccine candidate was found to protect rhesus monkeys from the new coronavirus (including its most concerning variants), as well as SARS and other SARS-related viruses that circulate in bats but haven't jumped to humans. That's an indicator, though by no means a guarantee, that the vaccine might also work in people.

"You would have protection against these variants that are circulating currently, but also you could have protection against any type of new SARS-related virus that might be similar to SARS-CoV-1 or SARS-CoV-2, that could originate from the bat species," Kevin Saunders, the institute's research director, told Insider.

The team's dream is to create a pan-coronavirus vaccine that could spell the end of coronavirus pandemics altogether.

"If you just look at history, there's been outbreaks of coronavirus about every eight to nine years," Saunders said. "What we're all working towards now is trying to figure out: Can we find a vaccine that would protect us against whatever the next coronavirus outbreak ends up being?"

At a White House briefing last week, Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said the research is "an extremely important proof of concept that we will be aggressively pursuing as we get into the development of human trials."

Saunders said the Duke researchers hope to start enrolling people in clinical trials as quickly as possible - somewhere between 18 months to two-and-a-half years from now.

Other research teams are also working on similar shots: More than two dozen pan-coronavirus vaccine projects are now underway, Science magazine reported in April.

The shot protected monkeys from variants identified in the UK, Brazil, and South Africa

The current COVID-19 vaccines seem to be effective against variants, but perhaps not to the same degree as against the original virus. Research has shown, for example, that existing vaccines may be less protective against B.1.351 and P.1 - the strains first identified in South Africa and Brazil, respectively - than against the original coronavirus strain or B.1.1.7, the variant first identified in the UK.

Saunders said his team's pan-coronavirus vaccine seemed to generate a stronger antibody response to all of these variants than the current vaccines have so far.

The researchers tested this by comparing their shot to an mRNA vaccine that resembled those from Pfizer and Moderna. The mRNA vaccine mounted a six-fold weaker antibody response against the B.1.351 variant and a 10-fold weaker antibody response against P.1 than against the original strain. But the pan-coronavirus vaccine only mounted a three-fold weaker antibody response against those variants.

"What was key here is that you start with really potent antibody responses, and then they just take a small decrease when they come in contact with one of the variants, compared to an mRNA vaccine that starts out lower and then takes an even bigger decrease when it tries to neutralize or block one of the variants," Saunders said.

It's not yet clear, though, how the pan-coronavirus vaccine would stack up against the booster shots being developed by Pfizer and Moderna.

The new vaccine candidate relies on a different technology than Pfizer and Moderna's shots. Both of the latter two instruct the body to produce the coronavirus' spike protein - which helps it attach to and enter cells. That, in turn, prompts our immune systems to produce antibodies to neutralize that protein. That way, if we ever encounter the virus in real life, our bodies can recognize it and fight it off.

Saunders' pan-coronavirus vaccine candidate, meanwhile, injects a fragment of the spike protein - one that's key to helping the virus invade our cells - into the body.

"The rationale was that if you could generate an immune response against that key part of the virus, then you would have protective responses that would limit the virus from being able to enter cells and replicate," Saunders said.

Preventing the coronavirus from becoming like the flu

Scientists predict that we'll never be fully rid of the new coronavirus, since not everyone in the world will choose to get vaccinated and some countries may take years to distribute shots.

"The thinking right now is that this virus has spread to so many parts of the world that there will always be some low level of endemic infection," Saunders said.

As long as the coronavirus spreads, it can mutate - which would necessitate periodic booster shots.

Take the seasonal flu (a descendant of the 1918 Spanish flu pandemic) as an example: Influenza viruses mutate very quickly, so we constantly have to update flu shots to vanquish new strains.

Scientists must choose which flu strains to protect against in vaccines almost a year in advance, so sometimes, the shots don't wind up matching the dominant strains in circulation. In a good year, flu shots are around 60% effective - but in a bad year, they might only be 20% effective.

The goal of a pan-coronavirus vaccine is to "become opposite of where the flu vaccine currently is," Saunders said.

"It wouldn't be a seasonal vaccination," he added. "It would be one that you received and then as long as your protective immunity stayed at a certain level, you wouldn't have to go back and be vaccinated again."